Search Results - "Craven, J D"

Quiet-time seasonal behavior of the thermosphere seen in the far ultraviolet dayglow by Strickland, D. J., Meier, R. R., Walterscheid, R. L., Craven, J. D., Christensen, A. B., Paxton, L. J., Morrison, D., Crowley, G.

“…The TIMED/GUVI instrument is a far ultraviolet spectrograph that obtains images in five spectrally resolved wavelength channels. These images yield information…”
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Multiple neutral density measurements in the lower thermosphere with cold-cathode ionization gauges by Lehmacher, G.A., Gaulden, T.M., Larsen, M.F., Craven, J.D.

“…Cold-cathode ionization gauges were used for rocket-borne measurements of total neutral density and temperature in the aurorally forced lower thermosphere…”
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Solar EUV irradiance variability derived from terrestrial far ultraviolet dayglow observations by Strickland, D. J., Lean, J. L., Meier, R. R., Christensen, A. B., Paxton, L. J., Morrison, D., Craven, J. D., Walterscheid, R. L., Judge, D. L., McMullin, D. R.

“…Remotely sensed ultraviolet emissions from the Earth's upper atmosphere are shown to mirror fluctuations in solar EUV irradiance during July 2002, including…”
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Assimilated observations of thermospheric winds, the aurora, and ionospheric currents over Alaska by Conde, M., Craven, J. D., Immel, T., Hoch, E., Stenbaek‐Nielsen, H., Hallinan, T., Smith, R. W., Olson, J., Sun, Wei, Frank, L. A., Sigwarth, J.

“…We present simultaneous measurements of thermospheric winds, auroral emissions, and ionospheric currents over Alaska, obtained from four separate instruments…”
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Evolution of the global aurora during positive IMF Bz and varying IMF By conditions by Cumnock, J. A., Sharber, J. R., Heelis, R. A., Hairston, M. R., Craven, J. D.

“…The DE 1 imaging instrumentation provides a full view of the entire auroral oval every 12 min for several hours during each orbit. We examined five examples of…”
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A survey of large-scale variations in thermospheric oxygen column density with magnetic activity as inferred from observations of the FUV dayglow by Nicholas, A. C., Craven, J. D., Frank, L. A.

“…Brightness of the terrestrial far-ultraviolet (FUV) dayglow is dominated by the 130.4-nm emission of neutral atomic oxygen, OI, and variations in the…”
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Exterior and interior polar cusps: Observations from Hawkeye by Chen, S.-H., Boardsen, S. A., Fung, S. F., Green, J. L., Kessel, R. L., Tan, L. C., Eastman, T. E., Craven, J. D.

“…Hawkeye plasma, magnetic field, and plasma wave instruments directly sampled the throat of the northern polar cusp as the orientation of the Interplanetary…”
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Evolution of the global aurora during positive IMF B z and varying IMF B y conditions by Cumnock, J. A., Sharber, J. R., Heelis, R. A., Hairston, M. R., Craven, J. D.

“…The DE 1 imaging instrumentation provides a full view of the entire auroral oval every 12 min for several hours during each orbit. We examined five examples of…”
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The visible imaging system (VIS) for the polar spacecraft by Frank, L. A., Sigwarth, J. B., Craven, J. D., Cravens, J. P., Dolan, J. S., Dvorsky, M. R., Hardebeck, P. K., Harvey, J. D., Muller, D. W.

“…The Visible Imaging System (VIS) is a set of three low-light-level cameras to be flown on the POLAR spacecraft of the Global Geospace Science (GGS) program…”
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Negative ionospheric storm coincident with DE 1-observed thermospheric disturbance on October 14, 1981 by Strickland, D. J., Daniell, R. E., Craven, J. D.

“…The DE 1 far ultraviolet (FUV) imaging instrument recorded a large thermospheric disturbance over Europe and Russia on October 14, 1981, during a geomagnetic…”
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Perturbations of the FUV dayglow and ionospheric storm effects by Prölss, G.W., Craven, J.D.

“…Decreases in the brightness of the FUV dayglow associated with magnetic activity are shown to be spatially correlated with negative ionospheric storms. Both…”
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Six days of thermospheric-ionospheric weather over the Northern Hemisphere in late September 1981 by Strickland, D. J., Craven, J. D., Daniell, R. E.

“…Thermospheric and ionospheric behavior over a 6‐day period beginning on September 24, 1981 (day 267), is discussed using DE 1 far ultraviolet dayglow data and…”
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An empirical model of the OI FUV dayglow from DE-1 images by Immel, T.J., Craven, J.D., Nicholas, A.C.

“…A refined empirical model of the Dynamics Explorer-1 far-ultraviolet (FUV) imaging photometer’s response to Earth’s quiet time FUV dayglow has been developed…”
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Measurement of the velocity of ultrasound in human cortical bone in vivo. Estimation of its potential value in the diagnosis of osteoporosis and metabolic bone disease by Greenfield, M A, Craven, J D, Huddleston, A, Kehrer, M L, Wishko, D, Stern, R

“…Using a method combining the velocity of ultrasound and photon absorptiometry in the human radius in vivo, the authors measured the speed of sound in bone (U)…”
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The effect of the momentum transfer on the sensitivity of a photon scattering method for the characterization of tissues by Leichter, I, Karellas, A, Craven, J D, Greenfield, M A

“…The ratio of coherent to Compton photon scattered by a tissue-like material depends on its effective atomic number. This ratio can, therefore, be used for the…”
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Fetal plasma renin and renin substrate in mid-trimester pregnancy by Symonds, E M, Craven, D J, Rodeck, C H

“…Blood samples were obtained by fetoscopy from 30 fetuses in the middle trimester of pregnancy. The results indicate that high concentrations of renin and…”
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Characterization of tissue via coherent-to-Compton scattering ratio: sensitivity considerations by Karellas, A, Leichter, I, Craven, J D, Greenfield, M A

“…It is known that the ratio (R) of the detected coherent and Compton scattered photons from bone can be used in order to determine its mineral density. This…”
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Quantitative assessment of bone mineral by photon scattering: calibration considerations by Leichter, I, Karellas, A, Shukla, S S, Looper, J L, Craven, J D, Greenfield, M A

“…The ratio of the coherent-to-Compton photons scattered from bone can be used to measure its mineral density. Conversion of this ratio (R) to bone mineral…”
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Quantitative assessment of bone mineral by photon scattering: accuracy and precision considerations by Shukla, S S, Karellas, A, Leichter, I, Craven, J D, Greenfield, M A

“…A method to determine the bone mineral density of the calcaneum has been reported earlier by our laboratory. In this method, the calcaneum is irradiated by a…”
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Trabecular bone mineral density measurement in vivo: use of the ratio of coherent to Compton-scattered photons in the calcaneus by Shukla, S S, Leichter, I, Karellas, A, Craven, J D, Greenfield, M A

“…Trabecular bone mineral density (TBMD) was measured in vivo in the calcaneus by a new method that uses the ratio of coherent to Compton-scattered photons…”
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